Time Course of Vision Loss
Determining the speed of onset of vision loss can aid the clinician in determining the etiology of the problem. Sudden onset (ie, within minutes) usually indicates an ischemic event, such as arterial occlusion. A course that evolves over days to weeks more typically denotes inflammation. Gradual progression over months or years is typical of compressive lesions, toxic or nutritional optic neuropathies (although such lesions may present more acutely), and glaucoma. It is important to differentiate between sudden loss of vision and sudden awareness of vision loss. Patients may become acutely aware of a chronic process only upon covering the uninvolved eye or only after the second eye becomes affected. Although the time course may suggest a cause of vision loss, the time courses of the various etiologies overlap considerably.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.